Envelope

This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Envelope" – news · newspapers · books · scholar · JSTOR (May 2011) (Learn how and when to remove this message) This article contains references that appear to be spam. Wikipedia is not a collection of links and should not be used for advertising. Please help improve this article by adding citations to reliable sources. See Wikipedia:External links and Wikipedia:Spam for details. (January 2023) (Learn how and when to remove this message) (Learn how and when to remove this message)

An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter or card.

Traditional envelopes are made from sheets of paper cut to one of three shapes: a rhombus, a short-arm cross or a kite. These shapes allow the envelope structure to be made by folding the sheet sides around a central rectangular area. In this manner, a rectangle-faced enclosure is formed with an arrangement of four flaps on the reverse side.